The present invention relates to an apparatus and method for separating and folding sections of a continuous web, in particular, to cutting and then folding multi-page forms in response to indicia on a continuous web. The present invention further relates, in particular, to cutting a continuous web slightly offset from a perforated or weakened line of folding to produce a tail or tab for each form which can be used to identify and separate the folded form from a stack.
The development of high speed printers has been accompanied by the need for improved devices to separate sections of continuous webs containing forms, printouts and reports. Multi-page web sections, forms, printouts, reports and the like are, as a group, referred to herein as forms, and a page is defined as extending between adjacent perforated or weakened lines of folding in a form or continuous web. Known devices typically burst or sever perforated or weakened lines of folding (hereafter, perforated lines) in a continuous web, and are suitable for separating continuous webs or a number of connected forms into stacks. The individual forms in each stack must thereafter be separated by hand.
Bursting devices, such as that disclosed by Irvine et al, U.S. Pat. No. 4,688,708, typically interrupt the progress of the continuous web to effect bursting. The speed of bursting devices remains limited despite improvements. Bursting devices typically find application in separating continuous webs which have been supplied to a printer pre-folded along perforated lines. Pre-folding weakens the perforated lines enabling bursting devices to typically separate forms prior to re-folding. However, the free leading edge of following forms or stacks are not entirely controlled and directed once separation has occurred. Once stacked, the forms in a stack must be identified and separated by hand.
Severing devices typically reciprocate a knife-like blade into a continuous zig-zag folded web at predetermined intervals to sever adjoining stacks along a perforated or weakened line. Typical of such devices is that shown by Uno et al, U.S. Pat. No. 4,508,527. The stack size which is produced is generally limited to a predetermined minimum and maximum number of forms, and separation of individual forms in each stack must, again, be undertaken by hand.
Other devices are known by which continuous webs may be severed transversely to cut single-page forms of predetermined length. Suter, U.S. Pat. No. 4,593,893 discloses transverse cutters which appear to operate in a scissors or guillotine fashion to cut single-page forms from a continuous web. Such cutters typically require interruption in the progress of the web for cutting. Feldkamper et al, U.S. Pat. No. 4,781,090 disclose a rotary cutter for severing single-page sections from a continuous web by transverse cuts in response to printed marks on the web. These severing devices permit successive separation of the web into single-page forms and have been limited to applications where no folding is required. The stacks of forms which result must still be sorted by hand.
Finally, various control systems have been developed to initiate the bursting or severing action of separating devices, such as those disclosed typically by Hoffman et al, U.S. Pat. No. 4,577,789, Meschi U.S. Pat. No. 4,618,340, and Feldkamper et al, wherein sensors detect printed marks or holes on the web and signal the separating device to act in a timed sequence to separate stacks or forms from the web. However, the control system of each separating device appears to vary with its construction and manner of operation.
Known devices can separate forms from a continuous web, however, their speed, versatility and manner of operation limit their usefulness with high speed printers. Many bursting, and scissors or guillotine severing devices require undesirable interruption in the progress of the continuous web. Severing devices with reciprocating blades have limited ability to accommodate the severing of short stacks, while rotary cutters accommodate only the cutting of short or single-page forms. More importantly, regardless of the separating device, individual forms within a stack must be separated and identified by hand.
Accordingly, further improvements are needed to satisfy the demand for more efficient and higher speed devices which can separate consecutive stacks and forms from a continuous web, and which can alleviate the burden of manual separation and sorting of forms in a stack.